1. Field
This application relates generally to wireless communication and more specifically, but not exclusively, to synchronization tests for device authentication.
2. Background
Wireless devices may employ a pairing process in an attempt to form a level of trust with one another in conjunction with authenticating with each other or exchanging cryptographic keys that may be used for services that are protected by cryptographic techniques. For example, in Bluetooth, authentication between two devices may involve the exchange of a passcode between the devices. In some implementations such a procedure may involve the use of a sophisticated user interface for passcode input. Conversely, in implementations that employ relatively simple user interface devices for passcode input, the associated provisioning cost may be relatively high. Moreover, a typical passcode used by users may be four to eight digits long, which may not be strong enough to prevent the security of the devices from being compromised by conventional cryptanalysis.
Bluetooth V2.1 proposes using elliptic curve Diffie-Hellman for key exchange. Here, based on a secret derived from elliptic curve Diffie-Hellman, device authentication may be based on numeric comparison or passkey entry. However, these methods may utilize a sophisticated user interface and may be relatively susceptible to man-in-the-middle attacks.
Near field communication technology also may be used for device authentication. For example, near field communication devices may be designed to perform a handshake only when they are brought within a defined “touching” distance of each other. It may be possible, however, to design a near field communication device with a custom antenna that extends the working distance for the handshake. In this case, an unauthorized person or device may be able to authenticate with another device from relatively long range thereby thwarting the security otherwise provided the requirement of relatively close proximity of the devices. Consequently, authentication that is based on a relatively small touching distance as provided by near field communication may not provide a sufficient level of security.